Richard Desmond is understood to have quietly made soundings about whether there is any appetite to potentially sell Channel 5 to rivals including ITV, just three years after he acquired it from pan-European broadcaster RTL.

ITV sources have confirmed that a very informal approach has been made through intermediaries, although it is notoriously difficult to divine Desmond's true intentions in testing the value of Channel 5 in the market. The approach is understood to have taken place several months ago.

Desmond is believed to be keen on concentrating on his publishing empire – which includes the Daily Express, Sunday Express, Daily Star and Daily Star Sunday as well as magazines including OK! – and has in the past expressed an ambition to buy the Sun from Rupert Murdoch's News International.

In 2011 a thin information memorandum circulated which implied that he was looking to offload a range of print assets, although nothing came of what associates of Desmond referred to as a "fishing expedition" to test the market value of his portfolio.

In a comment to MediaGuardian relating to that 2011 process, Desmond said: "As a private shareholder from time to time it is nice to value your assets."

A spokeswoman for Desmond's media company, Northern & Shell, denied that Channel 5 might be formally put up for sale.

"This is absolute nonsense, Channel 5 is not for sale and we have not had any discussions to that effect," she said.

Members of ITV's senior management team are understood to have informally discussed the idea of a Channel 5 bid, concluding that it was an unlikely prospect at the current time.

ITV's portfolio of channels command close to 50% of the total TV ad spend in the UK annually, making any bid for Channel 5 a near certainty for close scrutiny by the Competition Commission.

Nevertheless in 2010, ITV expressed an interest in buying Virgin Media's 50% stake in UKTV, owner of channels including Dave and Gold, which was eventually acquired by US TV company Scripps.

Separately, Desmond could potentially find scope for further cost savings by hiving off Channel 5's TV advertising sales under contract to Channel 4, which already handles airtime sales for UKTV.

Channel 4 controls about 28% of the total UK television advertising market and increasing much beyond this through a potential deal with Channel 5 is also likely to raise competition concerns.

ITV and Channel 5's terrestrial licences are currently in the final stage of renegotiation with Ofcom for a 10-year renewal, from the beginning of 2015 to 2024.

Channel 5 has said it was happy to renew without changes to its public service broadcasting commitments, and if Desmond were to sell after the licence renewal is finalised then any new owner would be bound by the terms, including a new commitment to broadcast at least 600 hours of UK-originated children's programmes a year as part of Milkshake, its kids strand.

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